Valve for rock drills



Jan. 13, 1931.

W. A. SMITH, JR

VALVE FOR ROCK DRILLS Filed Ded. 25, 1929 Uwk 2 III INVENTOR. mu 1 urn/H c7mt/1/rfa Hrs ATTORNEY.

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' exhaust I WasherE- Patented Jan. 13, 1931 E PATENroFmE WiLLIAM Aqsivtrmn, 3a., or rmmrrssuas} NEW JERSEY ASSIGNORTQINGERSGILL- v IRAIFIDYCOMPANY, or JERSEY errv, ew JERSEY," A CORPORATION on NEW JERSEY .vALvE FOR ROCK DIBILLS Application filed December 23, 1929. Serial No.' 116,132.

This invention relates to rock drills, but more particularly to a distributing valve for fluid actuated rock drills of the hammer type.

Afew of the objects are to obtain a rapid R and positive action of the valve and to simplify theconstruction of valve mechanism of this type. t t i Other objects will be in part obvious and in part pointed out hereinafter.

In the accompanying drawings illustrating the invention and in which similar referezice characters refer to similar parts,

:Figure 1 is a sectional elevation of a rock drill having the --inventionapplied thereto 15 and showing the valve in position to admit ipressure fluid into'the cylinder foractuating the hammer piston o its o k ng st o e, an igure 2- s t s iilar i sho ing th V valve andthe piston in their: other limiting V Jlie er i g m par cul rly t thezdraw ings, A d ignates a cylin e a ng a pi t n hamb B to aoc mm atea recip cato y hammer, piston I h cyl der A h s a ee port D Which iscontrolled by the Pisto G I 7 r t A suitable closure is providediorthe front end of the piston-chamber B by a frontcyltinder washer E which also serves to centralize 130 a front headF with respect to the cylinder; A.

The frontheadgF acts as aguide for a working impleme G :t wh ch t e blow o the hammer piston Care transmitted by an anvilbloch H guided by the front cylinder -l. e, rear end of t e cylin er Ais n nlarged bore J t-o accommodate a valve chest designated generally by K and comprising in this instance a pair of plates L and(). The

40 plate L isarranged in the rear end of the piston chamber for which itiforms a closure, and the plate Q is lHlBBBPOSQCl'bElJWQQll vthe plate L and'a back head Pavl ieh maybe clamped to the cylinder A in well known mannflr..- 7

Arranged within the hack headyP is a throttle valve Q having achamber R int-0 which pressure fluid may be constantly illtwduc d frame suitable source of supply In the Wall o the thro tle va is a sort S which, registers with. a pass ge '1 i the bas head for admittin pre su e. flu d into the rear ndof a valve cham er-U in th p ates L and Q. A V

:T'llG portion of the valve chamber U tor- 16 1 in tlleplate Lj'is an enlarged por on W, an the rear portion X of the valve'chamber U is ofsmaller diameter than the portion W aged is formed in theplate 0. Leading from the front end of thevalve'chamher U tothe rear end or the piston chamber B are inlet pas sages Ywhichare located in the frontend of the plate L. From the rearend of the enlargecl-porticn WV of thevalve chamberleads a front inlet passage Z which is formed in t p at s .Oand Lendin e-w of yl nder- A. t 7' 1i einlet passages Y and Z are co tbyz a distributing valve bin the valve QllZLHlh r The valve 6. compr ses a body p rt on c ha ing ab re d the ein which is in'c n an communication 'Wlth the passage T and through whi h p essure fluiclflovvs to he rear inlet passages ,Y.

At the front 'endof'the valvelb' is a head'a which cooperates sli'dably With the" enlarged to guide the ter than the enlarged portion W of the valve chamber wherein it lies; andthe pressure fluid "supplied-to tlieifront inlet passage Z forjimpelli lg th pist n C rearwardly fl w ove the pe iph ry otthe fl nge f to the in e here pl into the enlarged portion V] of the v lve chamberllenclab a p int termediate passage ,Z. The pressure fluid supply to the I irontinlet passage ,2 is conveyed from the flange f which is of somewhat smaller diames the head e and the flange f by ports 9 in the body portion 0 of the valve.

The rear end of the valve is in the form of a stem h which cooperates slidably with the portion X of the valve chamber and the end of the stem it constitutes a pressure surface j against which pressure fluid constantly acts tending to throw the valve forwardly;

On the rear end of the head e is a second pressure surface is which is also constantly exposed to pressure fluid for throwing the valve in a forwardly direction.

At the'front end of the valve 6 is an opposing pressuresurface 0 which is also constantly exposed to pressure fluid tending to throw the valve rearwardly. The pressure surface 0 is of considerably smaller area than the combined areas of the pressure surfaces 7' and so that in the absence of other forces tending to actuate the valve, the pressures acting against the pressure surfaces j and 70 will predominate over that acting against the pressure surface 0.

Additional means are provided to assist the pressure fluid acting against the constant pressure surfaces for throwing the valve from one position to the other. To this end the rear end of the flange 7 is provided with an actuating surface 39 against which compression from the front end of the piston chamber 13 intermittently acts to assist the pressure fluid actingagainst the pressure surfaces j and 7a to throw the valve 6 forwardly. Similarly, on the front end of the head 6 is an actuating surface 9 which overlies the inlet passages Y and against which compression from the rear end of the piston chamber B I acts to assist the constant pressure acting against the pressure surface 0 to throw the valve 6 rearwardly.

From I the foregoing description it is thought that the operation of the device will be apparent to those skilled in the art. This operation may however be briefly summarized and is as follows :With the valve in the position to admit pressure fluid to the rear end of the piston chamber B asindicated in Figure 1, pressure fluid will flow through the bore '0 into the front end of the valve chamber U, thence through the inlet passages Y into the rear end of the piston chamber to drive the piston C against the anvil block H.

7 During the admission of pressure. fluid into the rear end of the piston chamber B, pressure fluid will act against the entire front areaof the head 6 of the valve, and the valve will then remain immovable in the rear end of the valvechamber by reason of the fact that the effective area of the pressure surface 70 will then only be equal to the diiference between the'total area of said pressure surface and the areaof the flange f. i a Y As the piston moves forwardly and after it has covered the exhaust port D the air in the front end of the piston chamber B will be compressed. Such compression will flow through the front inlet passage Z and will act against the actuating surface 79 to throw the valve forwardly at the instant the rear end of the piston C uncovers the exhaust port D. The forwardly acting pressures will then predominateover the opposing pressures since when the piston uncovers the exhaust port D, there will be an abrupt drop in pressure beneath the head 0.

In the new position of the valve, the pressure fluid will flow from the bore d through the port 9 into the enlarged portion-w of the valve chamber, thence over the periphery of the flange f and through the inlet passage Z to the front end of the piston chamber B to drive the piston C rearwardly. o

The valve 6 will remain seated until sufficient compression is created in the rear end of the cylinder by the piston so that the combined forces of the compression acting against theactuating surface 9 and the pressure acting against the pressure surface 0, as well as the suction on the flange f created by the pressure fluid, will throw the valve again to its initial position, thus completing the cycle of operations.

I claim:

1. In a fluid actuated rock drill, the combination of a cylinder and a piston therein, a valve chest having a valve chamber, inlet passages leading from the valve chamber to the cylinder, a distributing valve in the valve chamber having a-bore through Whichpressure fluid flows to one inlet passage, said valve having a flange over which pressure fluid flows to the other inlet passage and a head slida-ble in the valve chamber to guide the valve, a port in the valve to convey pressure fluidfrom the bore into the valve chamber between the flanges, opposed pressure surfaces on the valve constantly exposed to pressure fluid tending to throw the valve, and opposed actuating surfaces intermittently exposed to compression to assist the pressurev fluid acting against the pressure sur- 7 faces 1n throwlng the valve upon a drop 1npressure beneath one or actuating surfaces. I 2. In a fluid actuated rock' drill, the combination of a cylinder and a piston therein, a valve chest having a valve chamber, front and rear inlet passages leading from the the other of the valve chamber to the cylinder, a distribut= ing valvein the valve chamber having a bore through which pressure fluid flows to the rear inlet passage, a port in the valve to convey pressure fluid into the valve chamher from the bore, a flange on the valve over which pressure fluidv flows to the rear'inlet passage, a head on the valve cooperating V slidably with the valve chamber to guide the valve, pressure surfaces'on one end ofthe valve and on the head constantly exposed to pressure fluid to throw the valve for opening the front inlet passage, an opposed pressure surface on the head constantly exposed to pressure fluid tending to throw the valve for opening the rear'lnlet passage, and opposed actuating surfaces on the head and the flange intermittently exposed to compression to assist the pressure acting against the pressure surface in throwing the valve upon a drop in pressure beneath one or the other of the actuating surfaces.

In testimony whereof I have signed this specification.

WILLIAM A. SMITH, JR. 

